Device for Controlling Functions of a Mobile Vehicle, and Method for Controlling Said Functions

ABSTRACT

A driving motor drives power-consuming devices and, via a clutch device, driving wheels as well. Upon actuation of a brake pedal, an electronic controller determines an input torque of the clutch device and disengages the clutch device when the brake pedal has reached a defined value that is dependent upon the input torque.

This application is a national stage completion of PCT/EP2005/001142filed Feb. 4, 2005 which claims priority from German Application SerialNo. 10 2004 006 790.2 filed Feb. 12, 2004.

FIELD OF THE INVENTION

The invention relates to a device for controlling the functions of amobile vehicle and a method for controlling these functions.

BACKGROUND OF THE INVENTION

In mobile vehicles, particularly in work machines such as wheel loaders,there is a need to obtain sufficient power for the hydraulic system evenwhen the service brake is actuated and thus the driving speed is low.

In work machines such as wheel loaders, on one hand, a driving motordrives the driving wheels via a hydrodynamic torque converter and aclutch device and, on the other hand, drives the power-consumingdevices, such as hydraulic pumps which, for example, the loading shovelof the wheel loader is operated. Wheel loaders comprise a controlfunction, as a result of which, at the beginning of the loadingoperation, the driving clutch is opened upon actuation of the servicebrake, this acts upon the vehicle wheels by disconnecting the hydraulicactuating pressure in a hydraulic, actuated clutch element. As a resultof the opening of the driving clutch, the engine power is availablealmost exclusively to the vehicle hydraulic system for actuating thepiston/cylinder arrangement of the loading shovel. Above all, this isassociated with the fact that without this control function a very highpower loss develops in the torque converter when the drive is connectedand the vehicle service brake is actuated, since the turbine wheel inthe converter has come to a complete or nearly complete halt, while thepump wheel, driven by the driving motor, rotates at the stall speed.

DE 102 30 993 A1 describes a method for controlling functions of anoccupational vehicle, where a driving motor drives vehicle wheels via adriving clutch, and a service brake acts upon the vehicle wheels, andthe driving motor drives a hydraulic pump, with the driving clutchbetween the driving motor and the driving wheels being automaticallyopened and the service brake being automatically closed when the loadacting upon the driving device of the vehicle, for example the weight ofthe loader shovel, exceeds a predefined load threshold or is actuatedsuch that DE 102 30 993 A1 describes a method for controlling functionsof an occupational vehicle, where a driving motor drives vehicle wheels,via a driving clutch; a service brake acts upon the vehicle wheels, andthe driving motor drives a hydraulic pump with the driving clutchbetween the driving motor and the driving wheels is automaticallyopened. The service brake is automatically closed when the load actingupon the driving device of the vehicle, for example, the weight of theloader shovel, exceeds a predetermined load threshold or is actuatedsuch that it exceeds this threshold. A wheel loader, however, mayencounter a plurality of driving situations in which it is not alwaysdesirable to automatically open the service brake and the clutch devicewith an exceeding load on the working device. For example, if the wheelloader travels up a ramp to the unloading site when feeding a crushingor sorting system, there is a possibility that the wheel loader isslowed down upon actuating the working device, although it has not yetassumed the final position. In the same way, based on the level ofdexterity, there is also the possibility that the clutch device isopened when the automatic system is not used, while the service brakehas not yet been sufficiently closed resulting in the vehicle rollingdown the ramp.

It is the object of the present invention to create a device forcontrolling the functions of a mobile vehicle and a method forcontrolling these functions in which a clutch device, which is setbetween the driving motor and the vehicle wheels, can be opened in orderto supply the power-consuming devices with sufficient power and therebyto take the different driving situations of the vehicle intoconsideration.

SUMMARY OF THE INVENTION

The driving motor drives a power-consuming device, according to theinvention, and, via a clutch device, also the driving wheels. Itcomprises a means for determining the input torque of the clutch device.The means is configured, for example, as electronic controllers, whichwith the presence of a hydrodynamic torque converter between the drivingmotor and the clutch device, use the determined rotational speedinformation, particularly the pump rotational speed as well as theturbine rotational speed of the hydrodynamic torque converter and thecharacteristic rotational speed line of the converter to determine theinput torque of the clutch device. Additionally, a means is provided fordetermining the deceleration request, which can be configured, forexample, as rotation angle sensors on the brake pedal or as pressuresensors in the brake lines. The clutch device is then opened when apreviously defined deceleration request and a previously defined torquehave been reached.

In another embodiment, a signal that is proportional to the brake pedalis fed to an electronic controller, which determines the input torqueupon recognizing a brake signal; then determines a deceleration requestthat was previously defined for this input torque, which may correspond,for example, to a defined pedal position and, upon achieving thisdeceleration request, actuates the clutch device so as to open it. Achange of the input torque between the initial actuation of the brakepedal and the time the deceleration request required for opening theclutch device is reached, for example, a sufficient pedal signal, is nottaken into consideration.

In another embodiment, the amount of the input torque influences therequired deceleration request in order to open the clutch device, forexample, upon actuation of the brake pedal, if a high input torque isdetermined because a wheel loader is driving up a ramp, the clutchdevice is only opened when a high deceleration request has been reached,which corresponds to an almost completely engaged brake pedal. Thisensures that the clutch device does not open too early, i.e., that theservice brake is not yet sufficiently closed, since this type of openingwould cause the vehicle to roll back if it were located on a ramp. If alow input torque is determined upon actuation of the service brake, theclutch device opens at a lower deceleration request and thus with ashort pedal path of the brake pedal. It is preferable to determine theinput torque when the brake pedal has been actuated, however, theservice brake has as yet caused no deceleration. By storing thecorrelation with the required deceleration request in an electroniccontroller, the clutch device is suitably opened at precisely thecorrect time for every driving situation.

BRIEF DESCRIPTION OF THE DRAWING

The invention will now be described, by way of example, with referenceto the accompanying drawing in which:

FIG. 1 shows a schematic illustration of the method for controlling thefunction of the mobile vehicle.

DETAILED DESCRIPTION OF THE INVENTION

Line 1 shows a determined input torque on a clutch device. Line 2 is abraking pressure acting upon a service brake and thus represents ameasure of the vehicle deceleration. Line 3 represents an engagingpressure for the clutch device, wherein at point 4, a clutch device isdisengaged, which is evident from a reduced actuating pressure appliedon the clutch. For example, if a mobile vehicle is traveling and thebrake pedal is actuated, as is shown at point 5, an electroniccontroller determines the input torque of the clutch unit. If a lowtorque is determined, as is shown at point 6, the clutch devicedisengages with a short pedal path, which is evident from line 7. If ahigh torque is determined, which is evident at point 8, then adistinctly larger pedal path is required in order to disengage theclutch device, which is illustrated with point 9 and line 10. Thisensures that with a distinctly higher input torque, the service brakeassumes a greater engaging state in order to prevent the vehicle fromrolling back as a result of the disengaging of the clutch device.

REFERENCE NUMERALS

-   1 line-   2 line-   3 line-   4 point-   5 point-   6 point-   7 line-   8 point-   9 point-   10 line

1-11. (canceled)
 12. A device for controlling functions of a vehiclehaving a driving motor connected, via a clutch device, to apower-consuming device and also to driving wheels, the devicecomprising: a device for decelerating the vehicle; a device fordetermining a deceleration request, and the clutch device being one ofengaged and disengaged depending on the deceleration request; and atorque-determining means for determining an input torque of the clutchdevice and for actuating the clutch device as a function of the inputtorque and the deceleration request.
 13. The device for controllingfunctions of the vehicle according to claim 12, wherein a hydrodynamictorque converter is located between the clutch device and the drivingmotor and comprises a pump wheel and a turbine wheel, the input torqueis determined from a rotational speed of the pump wheel, the rotationalspeed of the turbine wheel and a characteristic rotational speed line ofthe hydrodynamic torque converter.
 14. The device for controllingfunctions of the vehicle according to claim 12, wherein the decelerationrequest is determined from a position of one of a brake pedal and abraking pressure.
 15. A method for controlling functions of a vehiclehaving a driving motor driving, via a clutch device, a power-consumingdevice and also driving wheels, the method comprising the steps of:determining a deceleration request via device; decelerating the vehiclewith another device; one of engaging and disengaging the clutch deviceas a function of the deceleration request; and determining an inputtorque of the clutch device with a torque-determining device andactuating the clutch device as a function of the input torque and thedeceleration request.
 16. The method for controlling functions of thevehicle according to claim 15, further comprising the step of, above adefined deceleration request and above a defined input torque,disengaging the clutch device.
 17. The method for controlling functionsof the mobile vehicle according to claim 15, further comprising the stepof, when the deceleration request is recognized, determining the inputtorque.
 18. The method for controlling functions of the mobile vehicleaccording to claim 15, further comprising the step of, in an event oflow input torque with a low deceleration request, disengaging the clutchdevice, and in an event of a high input torque with a largerdeceleration request, disengaging the clutch device.
 19. The method forcontrolling functions of the mobile vehicle according to claim 15,further comprising the step of proportionalizing the decelerationrequest to one of a brake pedal path and a braking pressure.
 20. Themethod for controlling functions of the vehicle according to claim 15,further comprising the step of determining the input torque upon a firstdetection of the deceleration request, that a previously defineddeceleration request is associated with the input torque which, whenexceeded, will result in disengagement of the clutch device.
 21. Themethod for controlling functions of the mobile vehicle according toclaim 15, further comprising the step of detecting of the decelerationrequest prior to actuating service brake.
 22. The method for controllingfunctions of the mobile vehicle according to claim 15, furthercomprising the step of actuating a service brake starting with a defineddeceleration request.
 23. A device for controlling functions of avehicle having a driving motor connected, via a clutch device, to apower-consuming device and also to driving wheels, the devicecomprising: a device for decelerating the vehicle; a device fordetermining a deceleration request, and the clutch device being one ofengaged and disengaged depending on the deceleration request; and atorque-determining device for determining an input torque of the clutchdevice and for actuating the clutch device as a function of the inputtorque and the deceleration request.